WASHINGTON (CNN) --The U.S. Coast Guard is in the process of repatriating 531 Haitians intercepted on boats as they tried to make their way to the United States, U.S. officials told CNN on Friday.

The Haitians are fleeing the growing violence and turmoil fueled by rebel forces intent on removing President Jean-Bertrand Aristide from power. Armed gangs were looting and setting fires late Friday in the Haitian capital, Port-au-Prince, which rebels claimed they had surrounded. (Full story)

Nearly 300 of the migrants have been returned to Port-au-Prince.

They were ferried to land by Haitian Coast Guard boats after being transferred from the U.S. Coast Guard cutter Valiant Coast on Friday morning. Another 241 on the cutter Vigilant are expected to be brought ashore Friday after noon, also with the help of Haitian officials.

The two U.S. Coast Guard cutters are too big to go into the harbor. A third cutter is on hand to provide security, officials said.

Government sources told CNN that a few dozen Haitians have asked for asylum, expressing what are viewed as possibly credible fears that they would face torture if returned to Haiti. Those people are being kept aboard Coast Guard ships while their backgrounds are investigated.

A Coast Guard official said more Haitians were picked up Friday but there is no sign of a large-scale exodus.

"The repatriation of 531 Haitian migrants from three Coast Guard cutters is expected to be completed this afternoon," the Department of Homeland Security said in a written statement. "The Haitian migrants were rescued from a total of 13 boats in the Windward Pass over the past several days. The repatriation is being conducted in coordination with the Haitian authorities. The migrants are being turned over to the Haitian Coast Guard."

The United States also is considering dispatching a three-ship task force with more than 2,000 Marines to sit off the coast of Haiti as a precautionary measure, Pentagon officials told CNN on Friday.

They could -- for example -- assist if the number of Haitians leaving by boat became more than the Coast Guard can handle.